DETROIT — Fiat Chrysler Automobiles said Thursday its net profit soared to $1.9 billion for 2016 compared with just $100 million in the prior year when restructuring and recall costs dragged its earnings down.

It was driven to the big numbers by a huge performance in North America, but looking forward, the automaker faces some hefty challenges.

Issues range from a pending investigation by the Environmental Protection Agency into Fiat Chrysler’s diesel-emissions violations to how President Trump's changes to the North American Free Trade Agreement will effect the company. Also, the automaker faces a sweeping restructuring plan

But investors appear to be betting that the automaker is on the cusp of delivering on a plan to boost profit margins and thrive under the Trump administration. The automaker's stock price has soared more than 70%, from $6.30 per share on Oct. 21 to $10.95 per share Thursday, down 3 cents in midday trading — much larger gains than crosstown rivals Ford and General Motors.

In reporting its 2016 results, the company exceeded its own guidance to shareholders as it improved its profit margin in North America and increased sales in Europe.

Fiat Chrysler said it earned an adjusted net profit of $2.8 billion. Last fall, the company told investors it expected to earn more than $2.5 billion.

The company's performance improved as profit margins increased in North America and Europe.

In North America, Fiat Chrysler's pre-tax profit increased to $5.47 billion compared with $4.7 billion in 2015 even though sales dropped to 2.6 million vehicles, down from 2.7 million last year.

That boosted the company's North American profit margin to 7.4% for the year compared with 6.4% for 2015.